The present invention relates to forklift trucks, and in particular, relates to an improved method and apparatus for preventing fog and condensation from accumulating on a windshield of a forklift truck that traverses between environments having varying temperatures.
When operating a forklift vehicle at higher speeds in cold storage environments, where temperatures can typically reach as low as −25° F., a significant wind chill is experienced by the operator, thereby causing discomfort. It is therefore desirable to install a windshield in the truck that will protect the operator from the winds associated with operation of the forklift track in the cold environment and reduce operator discomfort.
However, because forklift trucks typically traverse between cold storage applications and warm environments, the windshield may experience significant temperature differentials of more than 100° F. Moreover, due to the cold air flow within the cold storage application, various locations on the windshield may be colder than others. Additionally, because the temperature of the cold storage application is commonly less than the dew point of the warmer environment, condensation can accumulate on the windshield when the truck travels from the cold storage application into the warmer environment. Subsequently, when the truck travels back into the cold environment, the condensation can freeze on the windshield. The condensation and frozen condensation can obstruct the operator's view. Furthermore, frozen condensation can render the forklift track unavailable for an extended amount of time.
As a result of the significant drawbacks currently associated with installing a windshield on forklift trucks that traverse between environments having significantly varying temperatures, a wire mesh is conventionally used in place of a windshield so as to prevent condensation from obstructing the operator's view. However, the wire mesh inadequately shields the operator from the potentially severe wind chills that are produced during operation of the forklift truck.
Because of these problems, heated windshield assemblies have also been constructed for use in forklift trucks operated in cold storage environments. These assemblies maintain appropriate temperature levels to reduce fogging and condensation from obstructing an operator's view, as discussed above, and have typically employed temperature sensors provided on the windshield to directly monitor the temperature. These heating devices, however, require additional components that add cost to the vehicle.